Yesterday, on our daily walk in the neighborhood, we found this strikingly patterned turtle in the middle of the road. It's a male Eastern Box Turtle, Terrapene carolina.
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| Male Eastern Box Turtle, Terrapene carolina |
The symmetrical orange markings in the middle of the upper shell are each in a separate scute. Each scute is a bony plate covered by a horny epidermis. As the turtle grows the scutes expand at the edges and the epidermis keeps pace with this growth, producing a ring on the margin of the scute. These rings of epidermis accumulate, one per year, and produce a "tree ring" like effect. You can clearly see the edges of each ring on the large scutes. Try to count them -- the number of rings indicates the approximate age of the turtle. Approximate because, as the turtle ages, the older epidermis rubs off causing a ring to disappear, so counting the scute rings is an under-estimate of the age. (I could make out somewhere between 10 and 15 rings on the scutes in the middle of the back. Did you get more or less?) So, conservatively, the turtle was between 10 and 15 years old. The shell was approximately 8 inches in length.
How did I know this is a male turtle? The lower shell, that covers the belly of the turtle, holds the secret. It is either flat or has a concave depression toward the tail half of the shell. If the depression is flat, the turtle is a female. Males have the depression.
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| Lower shell of box turtle showing the depression typical of male turtles. |
The photo above shows the underside of the box turtle. I hope you can make out the depression just to the right of the darker, damp area. Why would a male turtle have this depression? When turtles mate the curve of the female shell fits into the male shell depression, facilitating reproduction.
We moved the turtle off the road and released it in a more heavily vegetated area.
Box turtles have a diet that includes fungi, earthworms, fruits, and green leaves; in short, almost anything they can catch or reach. They appear to be major dispersers of Mayapple seeds. The turtle eats the fruit and, some distance away, defecates the unharmed seeds.
